(1) Affect of "fat servers" wiping out the small and midsized clusters.
I've noticed that "fat servers" like the 64-core systems with 1TB RAM
have decimated the small and midsized clusters. You can do in a single
4U box today what used to take a half-rack or much much more
(2) Affect of Hadoop/BigData on compute node configuration. We've
noticed a potential trend in our vertical (life science) where cluster
operators who need to make IT decisions now that have to live largely
unchanged for 2-4 years are looking at future HDFS/Hadoop requirements
and deciding to radically change their standard compute node footprint.
We've seen people abandoning the 1U pizzabox form factor and Blades in
favor of 4U servers that can be packed with local spindles in order to
support future HDFS and hardcore local processing requirements
(3) Storage is always a fun theme mainly because although compute is a
commodity it's still easy to have massive and interesting
price/performance/feature/architecture differences in the storage
systems people choose to roll out
My $.02